Although the Concept of Sustainability Is Appealing, It Is Subject

Although the concept of sustainability is appealing, it is subject to two principal issues, ________ and ________.

A) the lack of private initiatives; high budget deficits
B) how to increase the current employment rate; the challenges of attracting foreign investments
C) how to think about population growth; the difficulty of predicting future technological progress and innovation
D) the slow growth of the renewable energy industry; the difficulty in curbing emissions of greenhouse gases in developing countries